Answer:
The British soldiers were well trained and cared for, while the Americans were not career soldiers.
Explanation:
The term "underdog" is usually used to refer to the team or side that is presumed to be the weaker or losing side. This means that in any competition or fight, the underdog will be defeated and has lesser chances of winning the fight.
In the battle between the Americans and the British armies, the Americans were called the underdogs because of their background and complete ignorance in warfare. They were basically just guerilla fighters while the British armies were well trained and cared for.
Thus, the correct answer is the fourth/ last option.